Tobacco web material



Jan. '10, 1967 F. H.0SBORNE ETAL 3,297,039

TOBACCO WEB MATERIAL Original Filed Oct. 22, 1959 TOBACCO /0 EXTRA CT/NG WITH WA TER 30 /z sfPqmr/NG THE CONCENTRAT/NG AND I" 7x5 5 52? Ac/a/Fr/Nc ExTPAcT 32 5 I I DIGEST/N6 SEPARA Tnva I INSOLUBLES PREC/P/TA r: I I I I SEPAPA TING NEUTRAL/ZINC;

I THE PULP :5 THE ExTPAcT I 1 /8I I I L REF/N/NG PULP I ADD/N6 DYE AND 36 AND ADDING FILLER I HUMECTANT T0 34 l EXTRACT 1 I ADD/N6 FURT/l-I/VER I 38 REF/M 6 SATURAT/NG WEB CA F I WITH MODIFIED AGE/V 22 i EXTRAyCT AND 01-? we FORM/N6 WEB o/v I PAPER MAKING I I MACH/NE AND 40 3 DPY/NG I TREA TIA/6 was EMw/THNWAX ULS/O AND mm 28 1 DR F/BER JATURAT/NG WEB WIT/1' SOLUTION OF I 42 LINKING AGENT AND ALDEHYDE CAL ENDER/NG THEN DRY/N6 OR EMBOSS/NG uvmvrom FA Y H. OSBORNE WARREN J. BODENDORF United States Patent C) 3,297,039 TUBACQO WEB MATERIAL Fay H. Osborne, Windsor Locks, Conn, and Warren 1'. Bodendort, Montgomery, Mass, assignors to The Dexter Corporation, a corporation of Connecticut Original application Get. 22, 1959, Ser. No. 847,952, now Patent No. 3,145,717, dated Aug. 25, 1964.. Divided and this application Dec. 11, 1963, Ser. No. 329,803 12 Claims. (Cl. 131-47) This application is a divisional application of copending application, Serial No. 847,952, filed October 22, 1959, now US. Patent No. 3,145,717, which in turn was a continuation-in-part of application Serial No. 775,213, filed November 20, 1958, now abandoned.

The present invention relates to a new and improved tobacco web material and to a novel method of making same. A principal use of the tobacco Wfib' material of the present invention, although the invention is not limited thereto, is for forming tobacco webs for use as wrappers for cigars and cigarettes and for use as cigarette fillers.

Heretofore, the wrappers normally used for cigars have been natural tobacco leaf and the wrappers for cigarettes have been paper. In both cases, there are many adverse qualities in the wrapping material. The paper used for cigarette wrappers not only gives undesirable taste and odor, but in addition the products of combustion from the paper have been claimed to be the cause of harmful effects, such as lung cancer. The natural tobacco leaf used for cigar wrappers is generally of the most expensive grade and is difficult to use economically because the leaves are limited in size, are brittle and difficult to handle, and require a very large proportion of hand labor during manufacture of the cigars. In addition, there is no control as to the rate of burn, type of ash, undesirable constituents and strength, since the tobacco leaves are used as found in nature and there is no practical Way to modify the characteristics mentioned.

Many attempts have been made heretofore to produce continuous webs of tobacco by the use of various techniques and methods, but in general, such attempts have met with only limited commercial success and so far as is known, none of these prior methods has been successful in providing a tobacco web material suitable as an outer wrapper for cigars, although in some instances such web materials have been used as a binder. In general, the web materials of the prior art have been of relatively thick structure, undesirable in taste, aroma and appearance, and of limited strength. In addition, such web materials have been relatively expensive to produce, principally due to the slow production methods employed.

More recently it has been discovered that the incorporation of activated alumina in a tobacco sheet for use in cigarettes has the highly desirable effect of reducing the temperature of burning and the volatilization of alkaloids and suspected carcinogens.

The aim of the present invention is to provide a tobacco web material having the desirable characteristics of natural tobacco leaf but with many added advantages such as improved taste, strength, uniformity, burning characteristics, aroma, etc., and to produce this web in continuous lengths of desired width and thickness at relatively low cost so that the web may be used economically as a substitute for natural tobacco leaf, and, in brief, provide a better product than natural tobacco leaf at a lower cost to the eventual consumer. A further aim is to provide a novel method for manufacturing self-supporh ing tobacco web containing substantial amounts of activated alumina.

In general, the method of the present invention for forming a continuous web of tobacco comprises the steps of separating the water-soluble material from the insoluble portion of the tobacco, forming a web from the insoluble portion and then re-unitin-g the soluble portion with the insoluble portion in the final web. Certain novel steps in the treatment of the soluble and insoluble portions of the tobacco enable the provision of a tobacco Web having highly desirable characteristics, as will be fully described hereinafter. The insoluble material is formed into a web by the use of special techniques on papermaking machinery and thus can be made in wide Widths and in any desired length at relatively low cost. The web has a desirable appearance and is improved in taste, aroma and burning characteristics when compared with natural tobacco leaf. The final Web material may be formed in any desired thickness and strength rendering it suitable for use as a wrapper for cigarettes and cigars as well as a binder material; and because of its characteristics, automatic machinery may be employed to form the web into binders or wrappers for cigars and cigarettes, thus eliminating much hand labor.

The invention will be described in detail in connection with the accompanying drawing in which the single figure is a schematic and diagrammatic showing of a preferred method of carrying out the invention.

Referring to the attached drawing the tobacco feed for the process may be whole leaves, broken leaves, cuttings, stemming and various fragments or waste. For high grade cigar wrappers, only high grade tobacco leaves, or cuttings and stemmings from these leaves, are used. For cheaper cigar wrappers or for binders, lesser grade leaves and fragments may be used. If so desired, the tobacco may be shredded or cut into smaller particles which, however, is not necessary for the practice of the present invention.

The tobacco is first subjected to a Water extraction operation, designated by the numeral 10, wherein the tobacco is treated to separate the water-soluble constituents. This is most conveniently accomplished in a closed tank at elevated temperature, and minor quantities of chemical agents such as potassium carbonate may be added. The water used for the extraction is preferably pure, and deionized water may be used to advantage. Preferably only 1 to 3 parts of water per part tobacco are utilized to minimize the handling requirements for the subsequent evaporation, and extraction in a closed tank at about F. for one to two hours will be normally sufficient.

In the next step, designated generally by the numeral 12, the water-soluble constituents of the tobacco or extract are separated from the insoluble portion by any convenient process, such as draining, pressing and/or centrifuging. It is contemplated that the separated portions will normally be used immediately and thus no precautions are required. However, if the extract is not to be used soon after the extraction, refrigeration is required to prevent the formation of mold which would render the extract unusuable. Similarly, if the insoluble portion is not to be used immediately, it should either be dried such as by forming a dry pulp lap or, if it remains wet, it should be stored under refrigeration.

The insoluble portion of the tobacco is then subjected to chemical digestion, indicated generally by the numeral 14, to form a fibrous pulp. This treatment may be a caustic digestion utilizing 1 to 10 percent by weight of caustic (calculated as NaOH), and preferably 4 to 5 percent. It is most desirably carried out in a pressure tank at about 20 to 40 pounds per square inch pressure, and

preferably about 30 pounds. Generally, treatment at these pressures for two to four hours will be sufiicient. As a specific example, treatment with 5 percent by Weight of caustic for about three hours at 30 pounds per square inch pressure produces highly desirable results.

Alternatively, the digestion step may utilize nitric acid in an amount equal to about 15 to 40 percent by weight of the tobacco insolubles and preferably about 25 to 30 percent. The time for the treatment will vary with the temperature employed, but about three hours at 60 C. will normally be sufiicient. As will be readily apparent to those skilled in the art, this treatment requires special corrosion-resistant equipment, but has the advantage of operation at atmospheric pressure and lesser consumption of digesting agent. A further advantage is that the tobacco pulp produced is found to have a light, highly desirable tobacco color, thus eliminating any requirement for bleaching which might otherwise arise. As a specific example, treatment with 4 parts of 7 percent nitric acid per part tobacco insolubles (about 28 percent by weight HNO at 60 C. for three hours is quite satisfactory.

The digestion treatment produces a fibrous pulpy mass which is then separated from the digestion liquor in a step generally indicated by the numeral 16. This may conveniently be accomplished by draining and pressing.

The caustic digestion treatment is preferably so controlled by the amount of caustic added that the resultant pulp is neutral. However, the nitric acid treatment will produce an acid pulp which is then rinsed with water,

, neutralized with agents such as sodium hydroxide or sodium carbonate, and rinsed again.

' The tobacco pulp is then refined in a beater, as indicated by the numeral 18. In this step, the tobacco pulp is furnished to a regular papermaking beater and sufficient water is added to form a slurry containing approximately 1 to 7 pounds of pulp per 100 pounds of water. The tobacco pulp is refined by the beater roll in a brushing operation which macerates the fibers of the pulp. This operation will generally require about one-half hour. At this point a small amount of filler may be added to improve the ash formation of the final web, and agents such as titanium dioxide, clay, calcium carbonate, or alumina are desirably employed. The amount of filler added can vary over a wide range depending upon the end use. For cigar wrappers, the addition of 2 to 8 percent by weight of the filler based upon the final product gives satisfactory results, while for cigarette wrappers, additions of up to 15 percent produce desirable results.

If so desired, large amounts of activated alumina may be added to the tobacco fibers in the beater to produce a finished web incorporating the alumina for use in cigarettes and the like. Generally, the amount of activated alumina added for this purpose may vary to provide from 10 to 75 percent by weight of the finished sheet, and preferably between 50 to 65 percent by weight.

The activated alumina must be of sufficiently small particle size to disperse in the slurry and blend in the web, and should be of a particle size less than 200 mesh and preferably less than 325 mesh. Since the activated alumina added has a tendency to wash out with the water draining from the web, it is generally necessary to add an excess of alumina to the tobacco slurry to obtain the desired percentage in the final product. The actual ratio added to the slurry will vary with the machine employed, and the conditions of operation, and can be readily determined.

The slurry of tobacco pulp and inorganic material is then treated to further refine the tobacco pulp by running the slurry through a Jordan machine, or disc refiner, or both, as indicated by the numeral 20.

The tobacco fiber slurry thus prepared is formed into a web on a papermaking machine as indicated by the numeral 22. By way of example, there may be used a paper machine of the type shown diagrammatically in the Pay H. Osborne Patent No. 2,045,095, issued June 23, 1936, which is designed to run with very low fiber concentration in the headbox. However, other types of paper making machines may be used, such as a conventional Foudrinier machine. The tobacco slurry is admixed with water in the trough and headbox to provide a consistency of approximately 0.05 to 1.0 percent by weight solids. The thickness of the web may be varied over a wide range by varying the consistency of the slurry in the headbox.

As indicated by the numeral 24, an aqueous solution of a non-toxic cationic agent is simultaneously fed into the headbox in an amount equal to about 0.5 to 12.0 percent by weight of tobacco fibers, and this cationic agent will generally constitute about 0.05 to 6.0 percent of the finished sheet. In particular, cationic starch has proven highly beneficial for this purpose. As a specific example, 2 percent by weight cationic starch solution is fed into the headbox in an amount suflicient to provide about 5 pounds of starch per 450 pounds of fibers introduced.-

The addition of the cationic agent is found to improve the strength and drainage of the web, as well as act as a flocculating agent.

Although, in the present invention, digested tobacco fibers alone may be utilized to produce the web, in some instances it is desirable to add to the web a minor proportion of conventional papermaking fibers for added strength as indicated by the numeral 26. Generally, the conventional papermaking fibers added may vary from a small amount toa maximum of about 2 pounds per 15 pounds of tobacco fibers, and preferably less than 1 pound per 15 pounds. The conventional papermaking fibers are added to the headbox as a dilute slurry wherein they intermingle and admix with the tobacco fibers to form a composite web on the Foudrinier wire.

The particular conventional papermaking fibers selected will depend on such matters as cost and the amount of strength desired in the final web. For maximum strength, it is preferred to use manila hemp fibers having a fiber element length of 5 to 8 millimeters.

As an alternative to the chemical digestion of the insolubles, a tobacco web of lesser grade and quality can be prepared by more extensive maceration of the insolubles during the refining steps without chemical digestion, as indicated by the dotted line from steps 12 to 18 on the attached drawing. In this embodiment, the refining must be sufficient to cut the insolubles into small particles, and natural fibers must be admixed with the tobacco fibers in an amount sufiicient to provide a slurry containing 5 to 13 percent by weight of natural fibers.

An advantage of the method of the present invention is that by freeing the tobacco of water-extractable material prior to forming the web, much gelatinous material, such as pentosans, is removed and the resulting slurry,

being of a much less gelatinous nature, will drain sufficiently rapidly on a conventional Foudrinier wire screen to permit facile production and good uniformity of the web. Due to the low wet strength of the tobacco web at this point, it is necessary to provide the papermaking machine with a conventional felt carrier to transfer the web from the Foudrinier wire to the dryers. Upon completion of drying, the web may be rolled up as in any other papermaking process.

Next, the dried web is preferably treated to improve its wet. strength and other characteristics as indicated by the numeral 28, especially for preparation of a wrapper sheet. In this step, the web is saturated with a solution of aldehyde and a non-toxic cross-linkable agent selected from the group consisting of protein and polymeric alcohols, to which a humectant may also be added. The wet-strengthening is accomplished by cross-linkage and insolubilization of the protein or polymeric alcohol, which is preferably accelerated by a mineral catalyst, such as phosphoric acid. A preferred solution for this purpose may have approximately the following formula:

Percent by weight The polymeric alcohol, polyvinyl alchol, is most desirably employed, and the protein utilized may be soybean protein, casein, or any protein of the collagen type, such as gelatin. The protein or polymeric alcohol is added in an amount sufficient to provide about 2 to 8 percent by weight of aldehyde cross-linked material in the finished web, and preferably about 3.5 to 4.5 percent. The aldehyde is added in an amount suflicient to cross-link and insolubilize the protein or polymeric alcohol, and formaldehyde, acetaldehyde and glyoxal may conveniently be employed. If so desired, alcohol, such as ethyl or isoprophyl alcohol, may be added to the solution to facilitate penetration or wetting of the web. Saturation may be effected by spraying the solution thereonto or by running the web through a bath of the solution. After saturation, the web is dried on conventional papermaking machinery and rolled up in the usual manner for further processing.

Returning to the filtrate or extract which was separated from'the insoluble portion of the tobacco at step 12, the extract is concentrated by evaporation and acidified as indicated by the numeral 30. The concentration may be accomplished by any of the well-known methods, but is preferably conducted with as little agitation as possible and without vigorous boiling so as to avoid distilling out the more volatile taste and flavoring compounds. The extract is preferably concentrated to a specific gravity of 1.10 to 1.25.

Following concentration, the extract is acidified to a pH of 4 to 6, and preferably about 5. This acidification is conveniently carried out by use of a mixture of phosphoric acid and citric or other weak organic acids in a 1:1 to 1:2 ratio. Upon acidification, a precipitate forms which is comprised mainly of acid-insoluble proteins responsible for much of the bad taste and aroma when natural tobacco is burned.

If so desired, the extract may be decanted or otherwise separated from the precipitate, as indicated by the numeral 32, to obtain a milder tobacco sheet.

After acidification (and separation of the precipitate, if so desired), the extract is neutralized by the addition of potassium carbonate as indicated by the numeral 34. By neutralization, it is meant that the pH should be adjusted by the addition of potassium carbonate into the range of 6.5 to 7.2, and preferably 7.0 or slightly below. In this range, no excess carbonate ion will be introduced into the solution and substantially all that which is introduced will decompose in solution to evolve carbon dioxide. These steps of acidification and neutralization will introduce an amount of potassium sufiicient to form organic potassium salts of the water-soluble constituents of the extract in excess of the amount of potassium nitrate present, which relationship has been found essential to produce good burning properties in the final product. Carbonate ion, if present in the final web in any appreciable amount, would tend to interfere with the burning of the wrapper because of the evolution of carbon dioxide. By this modification of the extract, the subsequently impregnated sheet is found to have a uniform, moderate rate of burn, which is most desirable from the standpoint of a good cigar wrapper.

After neutralizatin, other desirable additives for the sheet are added to the modified extract as indicated by the numeral 36. Generally, these additives will be hu- Percent by weight Tobacco extract (about 50% solids) 82.5 Hurnectant 15.85 Dye 0.4 Polyvinyl alcohol 1.25

The humectant, which may be glycerin, sorbitol or propylene glycol, is added to impart flexibility to the web, and the dye is any vegetable coloring for obtaining the desired color in the finished web. The polyvinyl alcohol not only adds strength to the web but also functions as a non-tacky humectant.

The base web which had been prepared in the steps previously described is now treated with the modified tobacco extract as indicated at 38. The intention here is to put back into the web some or all of the desirable components taken out of the tobacco by the previous extraction; and this may be after removal of the undesirable components. The web is saturated with the tobacco extract in any convenient manner, such as by spraying or by running the web through a bath of the extract, and the web is then dried in a conventional manner and rolled up. As a result of this treatment, the web is rendered strong, flexible and easy to handle.

Following the foregoing treatment, the web is then impregnated with an emulsion of water and wax as indicated at 40. A preferred water-wax emulsion which may be used for this purpose is a dilute emulsion containing approximately 8 percent wax solids, preferably a wax of vegetable origin. The purpose of this step of the treatment is to give the final product a wax-like appearance and feel simulating that of natural tobacco leaf and a degree of water repellency approximating that of natural tobacco leaf. Polyvinyl alcohol may also be used for this purpose because of its non-tacky nature. After the web has been saturated by running it through the emulsion, it is dried and rolled up in the usual manner.

The final step in the method is indicated generally at 42 and comprises calendering and/ or embossing the final sheet. The calendering gives the product a uniform thickness and brings out the waxy appearance. The embossing gives the product more stretch and more tobacco leaf appearance. If desired, the embossing design can be a tobacco leaf design having stern and veins to make the product simulate natural leaf tobacco.

The final tobacco web should have a thickness of 0.0015 to 0.008 inch and preferably less than 0.004 inch. A most desirable tobacco wrapper is one having a thickness of about 0.0020 to 0.0030 inch after calendering. The alumina bearing sheet will generally be between 0.004 and 0.008 inch in thickness.

Some of the extract may be used as a component of the wet-strenghtening solution in step 28, as indicated by the dotted line between steps 34 and 28. The mineral constituents in the extract apparently catalyze the aldehyde cross-linking of the protein or polymeric alcohol. Additionally, the use of the extract in this step provides increased impregnation of the sheet due to the sizing effect produced by the wet-strengthening material. Although the extract may constitute the entire aqueous component of the wet-strengthening solution, it is preferable that it constitute less than about 50 percent by weight of solution because of the accelerating effect of the mineral constituents upon the aldehyde cross-linking. The impregnation of the web with the water-soluble constituents in the two steps 28 and 38 insures thorough distribution throughout the web.

In preparing a tobacco sheet containing alumina, the web from step 22 is impregnated with the extract and humectant. Wet strengthening is not essential since the sheet is shredded and employed in the body of the cigarette. Although modification of the extract is not essential for such sheet, the controlled rate of burn so provided is found desirable.

As above described, the method is employed to form tobacco web material of conventional tobacco color. If desired, the two components from the extraction step indicated generally at 14, namely, the soluble and the insoluble portions, may be given a preliminary bleaching or other decolorizing treatment, such as by use of hydrogen peroxide, to provide lighter shades or to facilitate subsequent dyeing. In fact, decolorizing may be carried out to a sufficient extent to provide a final web which is white in color and thus particularly desirable as a wrapper for cigarettes. It has been found that such decolorizing does not have an adverse effect upon the taste or aroma of the final product.

In order that the invention may be fully understood, the following are given by way of specific examples; but it will be understood that the invention is not limited thereto.

Example 1 One thousand pounds of tobacco leaves and stemmings were extracted with 1000 pounds of water for two hours at 190 F, in a closed extraction tank. No chemicals were added. The insoluble portion was separated from the extract by draining and pressing, and then was placed in a digestion tank together with 600 gallons of water and 6 gallons of 50 percent by weight caustic solution. The insolubles were digested for three hours at approximately 260 F. and 30 pounds per square inch pressure, after which the pulpy mass was separated from the digestion liquid by draining.

The pulpy mass was then placed in a conventional paper mill beater together with 1000 gallons of water, and refined by brushing for approximately twenty minutes. During the refining operation, the pulp was admixed with twenty pounds of titanium dioxide. After the refining operation in the beater, theslurry was transferred to a Jordan machine for further refining.

The refined slurry of tobacco fiber was then fed into the headbox of a conventional Foudrinier papermak-ing machine, and a dilute slurry of manila hemp fibers was simultaneously introduced in an amount sufficient to provide 1 pound per 15 pounds tobacco fibers. The consistency of the slurry of the two fibers in the headbox was about 0.27 percent by weight. Also introduced into the headbox was a 2 percent aqueous solution of cationic starch at a rate of about cc. per minute, or about 5 pounds per 450 pounds of tobacco fiber.

A dry web of about 16 pound weight (24 36"480 sheets) was thus produced, which was passed through an aqueous solution containing 3.6 percent by weight polyvinyl alcohol (completely hydrolyzed), 3.6 percent gly oxal, 0.1 percent phosphoric acid (86 percent), and 3.6 percent sorbitol, and then dried, the web now weighing about 17 pounds.

The extract of water-soluble tobacco constituents from the extraction step was evaporated to a specific gravity of about 1.20 and equalled about 240 pounds. The concen trated extract was acidified .by addition of /2 pound of citric acid and A poundphosphoric acid to a pH of about 5.0. After acidification, the extract was neutralized by the addition of 3.5 pounds of potassium carbonate to a pH of about 6.9. To the neutralized extract were added 1 pound of vegetable dye, 35 pounds sorbitol and 5 pounds of polyvinyl alcohol.

The web was then impregnated thoroughly with the modified extract and dried. Next, the web was run through a water-wax emulsion containing about 8 percent solids and dried, after which the web was embossed with a tobacco leaf design suitable for a cigar wrapper.

per 400 cc. of air.

Upon testing, the finishedweb was found to have a basis weight of 23.7 pounds (24" 36"480 sheets) and to be 0.0024 inch in thickness. A densimeter test indicated the porosity to be 686 seconds per 400 cc. air. The dry tensile strength (average) was 2344 grams per inch and the wet tensile strength (average) was 344 grams per inch.

Example 2 Tobacco leaves were extracted, digested and refined according to the procedure set forth in Example 1.

The slurry containing the tobacco fibers and filler was diluted with water to provide a headbox concentration of 0.25 percent by weight, and a 2 percent cationic starch solution was simultaneously added. No natural fibers were introduced into the headbox.

A web of about 16 pound basis weight was formed from the tobacco fibers and was then impregnated with an aqueous solution containing 3.6 percent by weight gelatin, 3.6 percentby weight glyoxal, 0.1 percent phosphoric acid and 3.6 percent sorbitol, after which it was dried. The web was then subjected to further processing in accordance with Example 1.

The finished web was found to have a basis weight of 25 pounds (24" 36"-480 sheets) and to have a thickness of about 0.0038 inch. Porosity was determined to be 222 seconds per 400 cc. of air in a densimeter test. Dry tensile strength (average) was found to 2250 grams per inch and the wet tensile strength 210 grams per inch.

Example 3 One thousand pounds of tobecco leaves and stemmings were extracted with 1000 pounds of water for two hours at 190 F. in a closed extraction tank. The insoluble portion was separated from the extract and digested together with 600 gallons of water and 6 gallons of 50 percent by weight caustic solution for three hours at approximately 260 F. and 30 pounds per square inch pressure,

after which the pulp was separated from the digestion liquor.

The pulpy mass was placed in a conventional paper mill beater together with 1000 gallons of water and refined by brushing for one-half hour, during which time 1500 pounds of activated alumina of less than 200 mesh particle size was added. The slurry thus produced was further refined by passage through disc refiner and fed to the headbox of a conventional Foudrinier papermaking machine; and a solution of 2 percent cationic starch was simultaneously added thereto at a rate of about 5 pounds per 450 pounds of tobacco fiber. The headbox consistency was about 0.7 percent by weight solids.

The extract of the water-soluble tobacco constituents was evaporated, acidified, and neutralized as in Example 1; and to the neutralized extract was added 35 pounds of sorbitol and 5 pounds of polyvinyl alcohol.

,The web produced on the papermaking machine was dried and then impregnated thoroughly with the modified extract, and dried again. The finished web was found to have a basis weight of 59.6 pounds (24 36"--480 sheets) and to contain 60 percent by weight of activated alumina.' The sheet was determined to be 0.0059 inch in thickness, and the porosity (densimeter) was 96 seconds The dry tensile strength (average) was 963 grams per inch.

Example 4 Tobacco leaves and water in the proportion of pounds tobacco to 660 pounds of water were placed in a closed extraction tank together with about 2 percent of potassium hydroxide based on the weight of tobacco.

The mixture was heated to 190 F. for three hours, following which the extract was separated. The insoluble portion of the tobac-co was placed in a paper mill beater with water in the proportion of 3 pounds tobacco to 360 pounds water and refined for approximately two hours. Titanium dioxide equal to about 6 percent by weight of the tobacco was added thereto during the beating operation. The mixture was further refined in a Jordan machine and screened to remove any large particles remaining, after which about 6 percent by weight of Karaya gum Was added to the slurry. The slurry thus prepared was fed to the headbox of a papermaking machine, and a slurry of hemp fibers, to 8 mm. in length, was added in a proportion of 1 pound of hemp to 9 pounds of tobacco. The headbox consistency was determined at 0.05 percent by weight solids. The web produced on the papermaking machine was dried and run through an equeous dispersion containing 3.6 percent gelatin, 0.5 percent calcium nitrate, 11 percent ethyl alcohol and 0.75 percent formaldehyde, and again dried.

The extract was evaporated to a specific gravity of about 1.07 and acidified by the addition of a 1:1 mixture of phosphoric and citric acids until a precipitate formed which was separated by filtration and discarded. The extract was then neutralized with potassium carbonate and mixed with additional materials to make a solution containing 87.70 percent tobacco extract, 1.56 percent gelatin, 0.39 percent dye, 2.35 percent glycerin, 7.80 percent ethyl alcohol, and 0.20 percent formaldehyde. The Web previously prepared was run through the modified extract and dried, following which the web was then run through a water-wax emulsion containing about 5 percent solids and again dried. The web was then calendered to form a final tobacco web suitable for use as a cigar wrapper material.

The final web was found to have a basis weight of 26.4 pounds (24" 36"-480 sheets) and to be 0.004 inch in thickness. The porosity (densimeter) was determined at 190 seconds per 400 cc. and the dry tensile strength 1 average) was found to be 1966 grams per inch. The wet tensile strength (average) was 315 grams per inch.

By the practice of the present invention, there is produced a homogeneous water-laid tobacco web of thin dimension which contains all the desirable portions of the original tobacco and which has controlled and uniform characteristics of dimension, color, type of ash, flexibility, strength, taste and aroma. If so desired, the web maybe made milder by removal of acid-insoluble proteins contained in the extract. The web may be made solely of tobacco fibers, or made with an added minor proportion of natural fibers for additional strength.

By the method of the present invention, large amounts of alumina may be incorporated in a tobacco web for use as a constituent in the tobacco filler of cigarettes and the like to reduce the burning temperature and the volatilization of the alkaloids and suspected carcinogens.

The final web may be given the appearance and feel of natural tobacco of varying types with the added advantages of improved taste, aroma and burning qualities, and with greater strength and dimensional form suitable for use on automatic machinery. The web can be tailored within reasonable limits to meet the specific requirements of the particular end use and may be made at high production speeds with conventional papermaking equipment, thus providing a product which is economical to produce in large quantity. A further advantage of the web material of the present invention is that it may be rolled up and stored indefinitely under ordinary storage conditions unlike tobacco Web materials proposed heretofore which normally require excess moisture and low temperature storage conditions in order to provide a satisfactory shelf life.

It will be apparent that variations and modifications will be possible within the skill of the art and all such variations and modifications are intended to be included within the scope of the invention.

We claim:

1. A tobacco material comprising a thin, continuous, water-laid, self-supporting web consisting essentially of tobacco fibers from which substantially all of the watersoluble constituents have been extracted, said web being strengthened by a cationic starch and said web further carrying an impregnation of completely alkali neutralized water-soluble constituents of natural tobacco.

2. The tobacco material defined in claim 1 wherein the neutralized water-soluble constituents are substantially free of acid-insoluble proteins.

3. The tobacco material defined in claim 1 wherein the neutralized water-soluble constituents include neutralized acid-insoluble proteins.

4. The tobacco material defined in claim 1 including a minor proportion of a wet strength agent comprising an aldehyde cross-linked material.

5. The tobacco material defined in claim 4 wherein said aldehyde cross-linked material constitutes about 2 to 10 percent by weight of the web.

6. The tobacco material defined in claim 1 including a minor proportion of conventional papermaking fibers.

7. The tobacco material defined in claim 6 including a minor proportion of a wet strength agent comprising an aldehyde cross-linked material.

8. The tobacco material defined in claim 7 including minor proportions of conventional papermaking fibers and an inorganic ash-forming filler.

9. The tobacco material defined in claim 1 wherein the web includes a minor proportion of ash-forming filler and the neutralized water-soluble constituents of natural tobacco include organic potassium salts thereof.

10. The tobacco web material defined in claim 1 wherein the tobacco fibers include chemically digested tobacco fibers bonded together by a papermaking bond.

11. The tobacco material defined in claim 10 wherein the web includes activated alumina.

12. The tobacco material defined in claim 11 wherein the web contains from 10 to percent by weight activated alumina and the neutralized water-soluble constituents of natural tobacco include organic salts thereof.

References Cited by the Examiner UNITED STATES PATENTS 70,386 11/1867 Arnd 131-143 X 1,016,844 2/1912 Moonelis 131-144 1,325,060 12/1919 Toms.

1,756,722 4/1930 Arnold et al. 131-17 1,949,012 2/1934 Frank 131-143 2,000,855 5/1935 Lippmann et al. 131-143 X 2,007,407 7/ 1935 Sadtler 131-17 2,029,494 2/ 1936 Loewenthal 131-143 2,158,565 5/1939 Andrews 131-17 2,547,730 4/1951 Arnold et al. 131-17 X 2,549,177 4/1951 Davidson 162-175 X 2,734,509 2/1956 Jurgensen 131-17 2,734,510 2/1956 Hungerford et al. 131-17 2,755,207 7/ 1956 Frankenburg 131-15 2,972,557 2/1961 Toulmin 131-17 3,006,806 10/1961 Schur 162-175 X 3,017,294 1/1962 Meisel 162-175 X OTHER REFERENCES The Production of Tobacco by W. W. Carner, page 335, published 1951 by the Blakiston Co., Philadelphia, Pa., SB-273-G3.

SAMUEL KOREN, Primary Examiner.

F. RAY CHAPPELL, Examiner.

MELVIN D. REIN, Assistant Examiner. 

1. A TABACCO MATERIAL COMPRISING A THIN, CONTINUOUS, WATER-LAID, SELF-SUPPORTING WEB CONSISTING ESSENTIALLY OF TABACCO FIBERS FROM WHICH SUBSTANTIALLY ALL OF THE WATERSOLUBLE CONSTITUENTS HAVE BEEN EXTRACTED, SAID WEB BEING STRENGTHENED BY A CATIONIC STARCH AND SAID WEB FURTHER CARRYING AN IMPRENATION OF COMPLETELY ALKALI NEURALIZED WATER-SOLUBLE CONSTITUENTS OF NATURAL TOBACCO. 